Field of the Invention
The present invention relates to mobile communication, and more particularly, to a method and device for reporting a buffer status of a terminal in a system to which heterogeneous wireless communication technologies are applied.
Related Art
Nowadays, an LTE-A based communication service may provide a much faster speed than wire Internet to users. Accordingly, a user equipment that may receive an IP based service based on a cellular network such as LTE-A is widely used. The user uses an Internet Protocol (IP) based service such as Voice over LTE (VoLTE) and audiovisual communication through a user equipment. It is estimated that such an LTE-A based wireless Internet service will further increase.
Various communication systems such as LTE or LTE-A and a Wireless Local Area Network (WLAN), mobile World Interoperability for Microwave Access (WiMAX), and High Speed Downlink Packet Access (HSDPA) in which a transmission speed, coverage per base station, mobility, and a data use cost are different may be used as a next generation mobile communication network. That is, a plurality of radio access technologies (RAT) may coexist, and the user may select and access a network according to preference or a peripheral communication environment.
Specifically, current mobile devices such as a smart phone and a smart pad simultaneously have a 4G long term evolution-advanced (LTE-A) interface and a wireless local area network (WLAN) interface. Further, mobile communication providers support a wireless Internet service through a WiFi zone as well as a 4G network having wide coverage.
As a service is provided to the terminal through such a cellular network and WLAN network, various portions such as handover and data offloading should be considered.